[DevTools] Introduced WebDeviceEmulationParams.

public/web/WebDevToolsAgentClient.h

Index: public/web/WebDevToolsAgentClient.h
diff --git a/public/web/WebDevToolsAgentClient.h b/public/web/WebDevToolsAgentClient.h
index 9d4a4339c70c1fde6cbca0a04994bdcf7ddccbc9..c1d0fec69d1f5d7f8b6760b0c7dc7c2300ce5988 100644
--- a/public/web/WebDevToolsAgentClient.h
+++ b/public/web/WebDevToolsAgentClient.h
@@ -36,6 +36,7 @@
 
 namespace blink {
 class WebString;
+struct WebDeviceEmulationParams;
 struct WebDevToolsMessageData;
 struct WebRect;
 struct WebSize;
@@ -99,6 +100,9 @@ public:
         const WebRect& screenRect, const WebRect& viewRect,
         float deviceScaleFactor, bool fitToView) { }
 
+    // Enables device emulation as specified in params.
+    virtual void enableDeviceEmulation(const WebDeviceEmulationParams& params) { }
+
     // Cancel emulation started via |enableDeviceEmulation| call.
     virtual void disableDeviceEmulation() { }